I know little of GW2 lore, but quick research tells me Zhaitan has this in the bag. Able to create his own undead army is pretty useful.

Yeah, because that's gonna help when the whole world is being blown up.

Originally Posted by Arkenaw

Deathwing. Zhaitan was beat by some airships shooting sparkles at him. It took the power of 4 other dragon aspects, the dragon soul and the focusing iris (we saw that things power in Theramore) to defeat deathwing.

The focusing iris' power can pretty much be summed up by one of Malygos' quotes: "The powers contained here are sufficient to destroy the world ten times over". Now of course he was talking about the Eye of Eternity all together, but truth is that the Focusing Iris was the eye of the storm.

Originally Posted by Gannicus

Zhaitan has a 1mile wingspan and has a body made up of many other dragons. :x

That's like saying that a Warcraft Abomination is the strongest form of humanoid just because it's made of multiple other humanoids. Obviously it isn't.

In all honesty Deathwing takes this, not every dragon can simply blow up a planet.

Well actually the combined might of all the races. Something to think of is that Zhaitan's army faces quite a bit more sophisticated opposition. That's something I liked about GWII. The Good Guys get siege engines, catapults, mortars, airships with cannons, etc. Races use their smarts to build war machines to fight with. They don't grab a sword and go try to bonk the dragon on the nose. During the last fight, yes weakened Zhaitan does come down to being shot down by the airship flagship with the heroes manning the cannons, but it took the whole army to fight back his forces.

In both cases, while the beings themselves are formidable opponents where they really shine is in their evil cunning. Both are good at subverting opponents to their cause and building an army that is stronger than their individual might and what makes them the real danger.

Because of that, I have to give it to zhaitan. his methods are a little more... permanent. If it were simply Deathwing and Zhaitan trapped in a room with a spork and told the first to disembowel the other wins, i'd have to give it to Deathwing.